Microstructural and mechanical characterization of duplex stainless steel grade 2205 joined by hybrid plasma and gas metal arc welding

Tolungüç, Burcu
In the present study, the applicability of the hybrid plasma arc welding, in which a keyhole is responsible of deep penetration and a filler wire electrode supplies a high deposition rate, was examined. The microstructural evolutions in grade 2205 duplex stainless steel plates joined by keyhole and melt-in techniques were investigated. The specimens obtained from welded plates having thickness of 8 mm were examined via optical and scanning electron microscopy. Metallographic investigations were supported by X-ray diffraction and energy dispersed spectra analyses by characterizing the phases formed after welding. Impact toughness properties, hardness profiles, and crack propagation behavior of welding zones were quantitatively and qualitatively compared for mechanical characterization. Fracture characteristics were determined via scanning electron microscopy examinations. It was observed that single-pass HPA weldment seemed to be free of secondary austenite precipitation in acicular form, which is inevitable in multi-pass conventional arc welding methods. Besides δ-ferrite was successfully kept under 70%, which is presented as a limit to not to deteriorate the mechanical properties of DSS. High linear welding speed and high power density supplied by HPAW presented narrower weld metal and heat affected zone with not only lower hardness but also higher impact toughness energies. Synergic effect of the keyhole formed by a plasma arc and the metal transfer supplied by gas metal arc gave reasonable dilution in the weld metal. Furthermore, fatigue crack growth tests revealed that crack propagation rates in HPAW joints were comparable to GMAW joints.


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Contrary to other keyhole welding applications on duplex stainless steels, a proper cooling time and a dilution were achieved during hybrid plasma gas metal arc welding that provided sufficient reconstructive transformation of austenite without sacrificing its high efficiency and productivity. Simultaneous utilization of keyhole and metal deposition in the hybrid welding procedure enabled us to get an as-welded 11 mm-thick standard duplex stainless steel plate in a single pass. Me examination on hybrid plas...
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Sheet metals are subjected to certain temperatures (25-200oC) and strain rates (1-10 s-1) during forming applications. These thermomechanical conditions may cause dynamic strain aging (DSA) in various grades of steels including dual phase (DP) steels. DSA represent itself as serrations in the stress-strain curves. Two grades of DP steels (DP590 and DP800) were studied systematically at different strain rates (10-3s-1-1s-1) and temperatures (25oC-400oC) to investigate the DSA effects on the mechanical proper...
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Yurtışık, Koray; Gürbüz, Rıza; Department of Metallurgical and Materials Engineering (2013)
Despite its high efficiency, autogenous keyhole welding technique leads to an excessive δ-ferrite formation in as-welded duplex stainless steels that leads to deterioration of the corrosion properties of the material, as well as its toughness. Developing the hybrid plasma-gas metal arc welding procedure for duplex stainless steels, a narrow gap and single-pass weldment on 11 mm-thick duplex stainless steel (grade 2205) plates has been achieved. Contrary to other keyhole techniques, such as Laser beam weldin...
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Citation Formats
B. Tolungüç, “Microstructural and mechanical characterization of duplex stainless steel grade 2205 joined by hybrid plasma and gas metal arc welding,” M.S. - Master of Science, Middle East Technical University, 2012.